Aluminum reduction cells have traditionally employed anode systems of two different types: prebaked carbon blocks arranged in the cell for individual height adjustment and replacement, and Soderberg or self-baking anodes in which a large mass of carbonaceous material, typically a mixture of pitch and coke, is supported in a casing over the cell. In the latter system, the heat of operating the cell bakes the anode in place as it is formed progressively. Then, as the carbon anode is consumed at its lower end, more anode paste is supplied on top to replenish the anode. Adjustment of the anode position in the cell may be accomplished by lowering the anode and its casing as a unit, or by lowering the anode within its casing, or combinations of both.
Some cells use a permanent anode casing which is mounted in fixed relation to the cell. This type of construction typically includes external support means for the permanent casing, such as removable channels or the like, and a jacking system for adjusting the anode position within the casing. One such arrangement, particularly for Soderberg cells having side-entry anode pins, includes a stack of channel members on opposite sides of the anode, with clearance holes for the pins. The fixed casing itself has corresponding slots that are elongated vertically to allow for lowering the anode with its electrical contact pins and their associated support channels as a unit relative to the anode casing. Before the lowermost channels come too close to the bath, the bottom row of support channels and associated anode pins can be removed and later reset at the top.